Such sanitary thin paper containing a thin paper treating agent including a moisturizing ingredient is well known and called lotion type. This kind of sanitary thin paper is also called lotion tissue but is differentiated from moistened-type wet tissue. This sanitary thin paper is not moistened and thus is treated in the same category as general non-moisturized tissue paper.
This kind of sanitary thin paper has excellent hand feel represented by softness, cashmere-like feel, smoothness, non-scrooping feel, and fullness, and is reduced in irritation to skin, as compared to the general non-moisturized thin paper. Accordingly, this kind of sanitary thin paper is frequently used for blowing a nose and taking facial skin care.
However, the conventional products of this kind of sanitary thin paper may vary in hand feel and physical properties depending on environment, due to the functions of moisture absorption and moisture desorption contributed by the moisturizing ingredient. For example, such conventional products may vary in hand feel depending on region, season and indoor environment of use, and therefore may not provide desired hand feel.
More specifically, the conventional products may deteriorate in moistness under a low-humidity environment and decrease in strength such as tearing strength and tensile strength under a high-humidity environment.
In addition, depending on a usage environment, the conventional tissue paper may discharge water and the boxes of the tissue paper absorb the discharged water with deterioration in strength. This causes the stacked boxes to be deformed and damaged during stacking in storage and the like.
Further, the conventional products need to contain a certain excess amount of thin paper treating agent in the sanitary thin paper so as to provide sufficiently favorable hand feel at a usage site under an ambient atmosphere, particularly, a dry atmosphere. This leads to weakened paper strength of the sanitary thin paper.
Meanwhile, some chemical agents including a gel composition have been suggested as thin paper treating agents. However, it is hard to let such an agent as it is contained uniformly in thin paper. This requires a complicated process of heating and diluting the agent for fluidization, and extends a time necessary for drying a diluted water content. Further, the thin paper with such an agent has problems of weakened paper strength and deteriorated bending rigidity and hand feel, due to uneven application of the agent or advanced dryness of a gel surface of the agent.    Patent Document 1: JP 3950400 B    Patent Document 2: JP 2007-203089 A